Redstone basics
''Basic redstone mechanics and logic Redstone Wire and Dust 'Redstone Dust - ''' 'Redstone ore''' is quite common and typically appears in veins containing 1–8 blocks. It shows up at elevations ranging from 1 to 16 blocks above the bottom of the map (for comparison, sea level is around 64 blocks above the bottom of the map). Below elevation 16, it occurs in about 0.7% of rock. Redstone is very commonly found near lava, sometimes in the vicinity of gold or diamond. Redstone ore requires no smelting to be used, instead dropping 4–5 piles of redstone dust when destroyed with pickaxes made of iron or diamond. If you click on (left or right) or step on a redstone ore, it will emit light of level 9. Though it is called an "ore" it is not a metal and cannot be smelted into a pure substance.'' ''Redstone Wire -'' Redstone wire will carry a charge 15 blocks, the darkness of the wire will change the longer it is. To make Redstone Wire, with Redstone Dust in your hand, right click on the block you want it on. ''Redstone Wire and Signal Strength -'' Whether a block is weakly or normally (strongly) powered affects how redstone wires interact with it. If redstone wire is adjacent in any direction to a block that is powered strongly then it will become active. It will not become active if the adjacent blocks are only weakly powered, with the exception of the block below it, which may be strongly or weakly powered to activate the wire. This is the reason that redstone wires may traverse multiple levels. '''''Powering Blocks and Devices Powering Blocks -'' Each block in Minecraft may be powered or unpowered. Think of a "powered block" as a cube of dirt or an empty space (though no truly empty Air block can be powered) that is invisibly electrified but safe to touch. Power may be transmitted from a powered block to one or more of the six directly adjacent blocks. To transmit power, a block must be either: *an active power source (a redstone torch), *the block to which a switch is attached (that is, the block under a pressure plate or the block on which a lever or button is mounted), *the block a switch is in, *the block above a redstone torch, or *an active power conductor (redstone wire that is immediately adjacent to a powered block). One must be careful to note that a redstone torch placed on the side of a block of dirt is actually part of the block next to the dirt, not part of the dirt block itself. Similarly, redstone wire that is placed on top of a block of dirt is part of the block above the dirt. However, if the block on which the redstone wire is placed becomes powered in any way, so does the redstone wire. Each actively powered block transmits power in several directions, depending on the contents of the block: *A redstone torch powers itself and the block directly above it, unless that block is air. Because of how redstone wires work, this also activates adjacent power conduits (redstone wire). *A pressure plate activates the block it is physically located in, as well as the block below (on which it is placed). *A lever, if placed on a wall, powers the block in which it is located and provides the block on which it is placed with weak power (see below). If placed on the ground, it powers the block in which it is located, but not the block on which it is mounted. *A button powers the block on which it is mounted. *Redstone wire Powers itself and the block below it, but only weakly powers the blocks horizontally adjacent to the ends of the wire. ''Powering Devices - '' A device, such as a door, a minecart track, or a block of TNT, is activated when an adjacent block is powered. As a simple example, placing a redstone torch next to a door will toggle the state of the door. Similarly, standing on a pressure plate immediately adjacent to a door will activate the door, plate powers itself. However, standing on a pressure plate two blocks away from a door will not activate the door, because the power does not reach the block next to or under the door. To power devices at a distance, the power must be conducted from the active power source to the device; redstone wire is used for this purpose. As noted above, the redstone wire is part of the block it is physically located in, not the block to which it is attached. Redstone wire, or dust, has two states: on (lit) and off (unlit). The simplest way to activate redstone wire is to put redstone torch or switch adjacent to the wire. It also works to have a torch or switch directly above redstone wire, attached to a wall. It also works to place a block above redstone wire, and then to put a switch on top of that block. A redstone torch is itself a powered device; its default state is "on", but it will be turned off if it receives power from the block to which it is attached. This feature, along with the use of wire to transmit power in particular directions over distance, is the basis for the advanced redstone devices and circuitry below. Care must be taken to follow the power rules precisely, or one might see unexpected results. For example, consider a pressure plate. Activating the plate will power the block underneath the plate as well as the block in which the plate resides. Nevertheless, redstone wire beneath this block will still be powered, because it is adjacent to the powered block above it. However, activating the plate will not turn off a redstone torch placed beneath the powered block -- in fact, placing a redstone torch under the block under the pressure plate will power it continuously, effectively disabling the plate. ''(Specific Powered Devices) Certain devices act in specific ways, for example: *If a block is powered, a redstone torch attached to it will be deactivated. *If a block is powered, a door on top of it or adjacent to it will toggle its state from open to closed or vice versa. (The actual state will depend, because doors were implemented unintuitively.) *If a block is powered, and it is a note block/dispenser, it will play/shoot once. *If a block is powered, and rails are above it, they will toggle shape. (You can still have the wiring power the rail directly.) (Common Errors to Avoid) The following are common errors to avoid: *Trying to power a block by putting activated redstone wire underneath it. Redstone wire powers blocks only horizontally at its ends. To power a block from below, use a redstone torch. *Trying to transmit power through a block that doesn't have any redstone wire on it. While a generic block (dirt, sand, gravel, etc) adjacent to the end of a wire can receive power, it will not transmit that power to wire on the other side, because it is not one of the blocks that can transmit power. If you have a block that you cannot move, send wire around it (including on top of it). *Switches on top of blocks are slightly buggy. If you put a switch on top of a block, make sure that it works properly immediately. Depending on what order the redstone and switch are placed, and what direction you are facing, and what direction the switch is facing, some combinations of these options will cause the switch to not power the block underneath at all. If it happens, to fix it, destroy the block, change positions, and try to put the block and switch down again.